From: Ran Xiaokai Inspired by commit 82d9ff648c6c ("mm: huge_memory: refactor anon_enabled_store() with set_anon_enabled_mode()"), refactor thpsize_shmem_enabled_store() using sysfs_match_string(). This eliminates the duplicated spin_lock/unlock(), set/clear_bit(), calls across all branches, reducing code duplication. Tested with selftests ./run_kselftest.sh -t mm:ksft_thp.sh, all test cases passed. Signed-off-by: Ran Xiaokai --- mm/shmem.c | 88 ++++++++++++++++++++++++++---------------------------- 1 file changed, 43 insertions(+), 45 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 3b5dc21b323c..0cc7872cc576 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -5526,6 +5526,29 @@ static ssize_t shmem_enabled_store(struct kobject *kobj, struct kobj_attribute shmem_enabled_attr = __ATTR_RW(shmem_enabled); static DEFINE_SPINLOCK(huge_shmem_orders_lock); +enum huge_shmem_enabled_mode { + HUGE_SHMEM_ENABLED_ALWAYS = 0, + HUGE_SHMEM_ENABLED_INHERIT, + HUGE_SHMEM_ENABLED_WITHIN_SIZE, + HUGE_SHMEM_ENABLED_ADVISE, + HUGE_SHMEM_ENABLED_NEVER, +}; + +static const char * const huge_shmem_enabled_mode_strings[] = { + [HUGE_SHMEM_ENABLED_ALWAYS] = "always", + [HUGE_SHMEM_ENABLED_INHERIT] = "inherit", + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = "within_size", + [HUGE_SHMEM_ENABLED_ADVISE] = "advise", + [HUGE_SHMEM_ENABLED_NEVER] = "never", +}; + +static unsigned long * const huge_shmem_orders_by_mode[] = { + [HUGE_SHMEM_ENABLED_ALWAYS] = &huge_shmem_orders_always, + [HUGE_SHMEM_ENABLED_INHERIT] = &huge_shmem_orders_inherit, + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = &huge_shmem_orders_within_size, + [HUGE_SHMEM_ENABLED_ADVISE] = &huge_shmem_orders_madvise, +}; + static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -5551,57 +5574,32 @@ static ssize_t thpsize_shmem_enabled_store(struct kobject *kobj, const char *buf, size_t count) { int order = to_thpsize(kobj)->order; + int mode, m; ssize_t ret = count; + int err; - if (sysfs_streq(buf, "always")) { - spin_lock(&huge_shmem_orders_lock); - clear_bit(order, &huge_shmem_orders_inherit); - clear_bit(order, &huge_shmem_orders_madvise); - clear_bit(order, &huge_shmem_orders_within_size); - set_bit(order, &huge_shmem_orders_always); - spin_unlock(&huge_shmem_orders_lock); - } else if (sysfs_streq(buf, "inherit")) { - /* Do not override huge allocation policy with non-PMD sized mTHP */ - if (shmem_huge == SHMEM_HUGE_FORCE && !is_pmd_order(order)) - return -EINVAL; + mode = sysfs_match_string(huge_shmem_enabled_mode_strings, buf); + if (mode < 0) + return -EINVAL; - spin_lock(&huge_shmem_orders_lock); - clear_bit(order, &huge_shmem_orders_always); - clear_bit(order, &huge_shmem_orders_madvise); - clear_bit(order, &huge_shmem_orders_within_size); - set_bit(order, &huge_shmem_orders_inherit); - spin_unlock(&huge_shmem_orders_lock); - } else if (sysfs_streq(buf, "within_size")) { - spin_lock(&huge_shmem_orders_lock); - clear_bit(order, &huge_shmem_orders_always); - clear_bit(order, &huge_shmem_orders_inherit); - clear_bit(order, &huge_shmem_orders_madvise); - set_bit(order, &huge_shmem_orders_within_size); - spin_unlock(&huge_shmem_orders_lock); - } else if (sysfs_streq(buf, "advise")) { - spin_lock(&huge_shmem_orders_lock); - clear_bit(order, &huge_shmem_orders_always); - clear_bit(order, &huge_shmem_orders_inherit); - clear_bit(order, &huge_shmem_orders_within_size); - set_bit(order, &huge_shmem_orders_madvise); - spin_unlock(&huge_shmem_orders_lock); - } else if (sysfs_streq(buf, "never")) { - spin_lock(&huge_shmem_orders_lock); - clear_bit(order, &huge_shmem_orders_always); - clear_bit(order, &huge_shmem_orders_inherit); - clear_bit(order, &huge_shmem_orders_within_size); - clear_bit(order, &huge_shmem_orders_madvise); - spin_unlock(&huge_shmem_orders_lock); - } else { - ret = -EINVAL; + /* Do not override huge allocation policy with non-PMD sized mTHP */ + if (mode == HUGE_SHMEM_ENABLED_INHERIT && + shmem_huge == SHMEM_HUGE_FORCE && !is_pmd_order(order)) + return -EINVAL; + + spin_lock(&huge_shmem_orders_lock); + for (m = 0; m < ARRAY_SIZE(huge_shmem_orders_by_mode); m++) { + if (m == mode) + set_bit(order, huge_shmem_orders_by_mode[m]); + else + clear_bit(order, huge_shmem_orders_by_mode[m]); } + spin_unlock(&huge_shmem_orders_lock); - if (ret > 0) { - int err = start_stop_khugepaged(); + err = start_stop_khugepaged(); + if (err) + ret = err; - if (err) - ret = err; - } return ret; } -- 2.25.1 From: Ran Xiaokai Replace the hardcoded if/else chain of test_bit() calls and string literals in thpsize_shmem_enabled_show() with a loop over huge_shmem_orders_by_mode[] and huge_shmem_enabled_mode_strings[] arrays. This makes thpsize_shmem_enabled_show() consistent with thpsize_shmem_enabled_store() and eliminates duplicated mode name strings. Signed-off-by: Ran Xiaokai --- mm/shmem.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 0cc7872cc576..93fb0a5dca5c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -5553,20 +5553,30 @@ static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { int order = to_thpsize(kobj)->order; - const char *output; - - if (test_bit(order, &huge_shmem_orders_always)) - output = "[always] inherit within_size advise never"; - else if (test_bit(order, &huge_shmem_orders_inherit)) - output = "always [inherit] within_size advise never"; - else if (test_bit(order, &huge_shmem_orders_within_size)) - output = "always inherit [within_size] advise never"; - else if (test_bit(order, &huge_shmem_orders_madvise)) - output = "always inherit within_size [advise] never"; - else - output = "always inherit within_size advise [never]"; + int active = HUGE_SHMEM_ENABLED_NEVER; + int len = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(huge_shmem_orders_by_mode); i++) { + if (test_bit(order, huge_shmem_orders_by_mode[i])) { + active = i; + break; + } + } + + for (i = 0; i < ARRAY_SIZE(huge_shmem_enabled_mode_strings); i++) { + if (i == active) + len += sysfs_emit_at(buf, len, "[%s] ", + huge_shmem_enabled_mode_strings[i]); + else + len += sysfs_emit_at(buf, len, "%s ", + huge_shmem_enabled_mode_strings[i]); + } + + /* Replace trailing space with newline */ + buf[len - 1] = '\n'; - return sysfs_emit(buf, "%s\n", output); + return len; } static ssize_t thpsize_shmem_enabled_store(struct kobject *kobj, -- 2.25.1